Table Of Content

6 Coating of Steel Structures Hydroblasting and Coating of Steel Structures Hy d r o bI a st i ng and Coating of Steel Structures Andreas W. Momber Privatdozent, Department of Mining, Metallurgy and Earth Sciences, RWTH Aachen Germany ELSEVIER UK Elsevier Ltd, The Boulevard, Langford Lane, Kidlington, Oxford OX5 lGB, UK USA Elsevier Inc, 360 Park Avenue South, New York, NY 10010-1710, USA JAPAN Elsevier Japan, Tsunashima Building Annex, 3-20-12 Yushima, Bunkyo-ku, Tokyo 11 3,J apan Copyright 0 2003 Elsevier Science Ltd. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic tape, mechanical, photocopying, recording or otherwise, without permission in writing 6-om the publishers. Cover illustration: Courtesy of Muhlhan Surface Protection International GmbH, Hamburg, Germany British Library Cataloguing in Publication Data Momber, Andreas W., 1959- Hydroblasting and coating of steel structures 1.Water jet cutting 2.Stee1, Structural - Cleaning 3.Building, Iron and steel - Cleaning 1.Title 620.1’06 ISBN 185617395X Library of Congress Cataloging-in-PublicationD ata Momber, Andreas W., 195 9 - Hydroblasting and coating of steel structures / Andreas W. Momber p. cm. Includes bibliographical references and index. ISBN 1-85617-395-X (hardcover) 1. Steel, Structural - Corrosion. 2. Corrosion and anti-corrosives. I. Title. TA467 .M545 2002 620.1’723 -dc2 1 2002040768 No responsibility is assumed by the Publisher for any injury andlor damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the material herein. Published by Elsevier Advanced Technology, The Boulevard, Langford Lane, Kidlington, Oxford OX5 lGB, UK Tel: +44(0) 1865 843000 Fax: +44(0) 1865 843971 Typeset by Newgen Imaging Systems (P) Ltd, Chennai, India Printed and bound in Great Britain by Biddles Ltd, Guildford and King’s Lynn Contents List of Symbols and Abbreviations Used vii 1 Introduction 1.1 Definitions of surfaces and preparation methods 1.2 Importance of surface preparation processes 1.3 Subdivision of water jets 1.4 Industrial applications 2 Fundamentals of Hydroblasting 17 2.1 Properties and structure of high-speed water jets 18 2.2 Basic processes of water drop impact 24 2.3 Parameter influence on the coating removal 29 2.4 Models of coating removal processes 38 3 Hydroblasting Equipment 45 3. I High-pressure water jet machines 46 3.2 Pressure generator 47 3.3 High-pressure hoses and fittings 55 3.4 Hydroblasting tools 59 3.5 Nozzle carriers 63 3.6 Hydroblasting nozzles 66 3.7 Vacuuming and water treatment systems 73 4 Steel Surface Preparation by Hydroblasting 77 4.1 Efficiency of hydroblasting 78 4.2 Cost aspects 84 4.3 Problems of disposal 87 4.4 Safety features of hydroblasting 94 5 Surface Quality Aspects 113 5.1 Surface quality features 114 5.2 Adhesion strength 114 5.3 Flash rust 121 5.4 Non-visible contaminants - salt content 126 vi Contents 5.5 Embedded abrasive particles 133 5.6 Wettability of steel substrates 136 5.7 Roughness and profile of substrates 138 5.8 Aspects of substrate surface integrity 144 6 Hydroblasting Standards 149 6.1 Introduction 150 6.2 Initial conditions 151 6.3 Visual surface preparation definitions and cleaning degrees 152 6.4 Non-visible surface cleanliness definitions 154 6.5 Flash rusted surface definitions 155 6.6 Special advice 157 7 Alternative Developments in Hydroblasting 159 7.1 Pulsed liquid jets for surface preparation 160 7.2 Hydro-abrasive jets for surface preparation 169 7.3 High-speed ice jets for surface preparation 176 7.4 Water jethltrasonic device for surface preparation 181 References 183 Appendix 199 Index 203 ~ ~ List of Symbols and Abbreviations Used model parameter jet structure parameter cleaned surface cleaning rate nozzle (orifice) cross section plunger cross section jet structure parameter fatigue parameter cleaning energy flux speed of sound water constant speed of sound target paint consumption jet spreading coefficient paint degradation rate drop diameter maximum drop diameter Sauter diameter (water drop) dry film thickness hose diameter jet diameter nozzle (orifice) diameter plunger diameter threshold nozzle diameter cleaning effectiveness kinetic energy hydro-abrasive jet cleaning efficiency kinetic energy water jet Young’s modulus kinetic energy abrasive particle specific energy frequency pulsating liquid jet